1. Field of the Invention:
The present invention relates to centrifugal separators for separating a solids-and-liquid mixture into solids and a liquid by means of centrifugal force, and more particularly to such a centrifugal separator which is equipped with a filter on which solid components remain after removal of liquid components.
2. Description of the Prior Art:
An example of such centrifugal filter-type separator is disclosed in U.S. Pat. No. 4,193,874. The disclosed centrifugal separator, as shown here in FIG. 7 of the accompanying drawings, includes a drive unit A, a filtration unit B and a cake-discharge unit C. The drive unit A includes an outer shaft D drivable by a motor (not shown) and rotatably supported by a bearing E, and an inner shaft F fixedly secured by a key, for example, to the outer shaft D for corotation therewith. The filtration unit B includes a basket G secured to the outer shaft D, and a rotor H disposed inside the basket G and secured to the inner shaft F so that the basket G and the rotor H are rotatable concurrently with each other. The basket G has formed in its peripheral wall a number of perforations or pores G' for removing liquid components. The thus removed liquid components are collected to and then discharged from a discharge hole J in a casing I which contains the filtration unit B. The rotor H is slidably movable in a direction parallel to the axis of the basket G and includes a closure means for closing an open end of the basket G when the rotor H is received in the basket G. Extending between the basket G and the rotor H is a tubular or hollow cylindrical filter K formed of a woven fabric or the like. The filter K is overturned in response to the sliding movement of the rotor H in such a manner that the filter K is received in the basket G during filtration, and when a cake is discharged, the filter K is forced into the cake-discharge unit C while being turned upside down. The filter K is rotatable together with the basket G and the rotor H. The basket G is provided with a screen L of a corrugated cross section fixedly secured to an inner peripheral surface of the basket G for providing passageways for liquid components and also for preventing the filter K from being withdrawn into the discharge hole J.
In operation, the rotor H is received in the basket G, then while keeping this condition, a solids-and-liquid mixture to be separated is supplied into the filtration unit B through a feed pipe M which is disposed along the common axis of the rotor H and the basket G. The drive unit A is driven to rotate the basket G, the screen L, the filter K and the rotor H concurrently at high speeds, thereby removing liquid components from solid components by means of centrifugal force. In this instance, the liquid components are forced to flow successively through the filter K, the screen L and the pores G' in the basket G into the discharge hole J of the casing I. The solid components (cake) retain on the filter K placed inside the basket G. After removal of the liquid components, the rotor H is displaced from within the basket G to the cake-discharge unit C during which time the filter K is overturned, thereby removing the solid components from the filter K. The thus removed solid components is then discharged from a cake-discharge hole N.
The conventional centrifugal separator described above is however not fully satisfactory in that the firm attachment of the screen L to the basket G inhibits a free access to a space between the screen L and the basket G which is required for cleaning the space.
A further problem is that an improved effect to prevent withdrawal of the filter K into the screen L can only be attained by a double-layered screen L which is however complicated in construction.